Modified Technique for Laryngeal Mask Airway Insertion

Insertion of the laryngeal mask airway (LMA) is often smooth, atraumatic, and successful on the first attempt. It has been my observation, as a practicing private practitioner anesthesiologist and teaching physician in an academic institution, supervising residents and certified registered nurse anesthetists, that, just as often, insertion of a LMA takes more than one attempt and is clearly not as smooth and easy as expected. Less frequently, a bloody LMA tip is seen between attempts, which is the result of excessive force used to push the LMA into position. Various techniques of LMA insertion are used and taught by practitioners. This variability in itself represents, in my opinion, recognition of the fact that no single technique is ideal and no technique suitable for all patients. I believe that some of the difficulty in LMA insertion arises from the flexibility in the tube connecting the laryngeal portion to the breathing circuit, which necessitates the operator's applying directional force on the tube to lead the LMA into position past the different axes of the airway and, particularly, the base of the tongue. I have found that insertion of a rigid stylet into a partially inflated LMA and creation of a 90° angle close to the laryngeal portion of the LMA helps, significantly, to increase the rate of first-attempt successful insertion for all practitioners (Fig. 1). The rigid stylet and the angle created change the insertion from the art of applying the correct amount of force and in the right direction to a simple wrist motion, similar to insertion of a laryngoscope behind the base of the tongue. After insertion and removal of the stylet, the LMA is allowed to regain its flexible design and to conform to the anatomy of the patient. Care must be taken not to insert the stylet beyond the lumen of the flexible LMA tube and, potentially, injure the patient (just as with endotracheal tubes). Lubrication of the stylet would assist with a smoother stylet removal.Figure 1: LMA with rigid stylet in it, giving it the shape needed to insert it behind the base of the tongue.The idea of stiff LMA tubing was addressed by the company in producing the so-called intubating LMA. This device has several other modifications for the purpose of intubating the trachea via the LMA and was not made to improve LMA insertion. The cost of such device is more than twice the cost of a standard LMA. The modification I am proposing adds no cost to the current LMAs in use (Fig. 2). Further studies may be appropriate to examine this observation and to compare the various insertion techniques.Figure 2: Comparison of nonstyleted LMA and the styleted LMA (as proposed by the new insertion technique) commercially manufactured “intubating LMA” with a similar angulation.Uriel A. Yodfat MD